Why Greenhouse takes the piss


By Kelly On April 4, 2012

Did you enjoy a refreshing cider, smooth coffee or fruity cocktail at the recent MFWF Greenhouse by Joost? If so, there’s a good chance you contributed to the 2500 litres of urine that was collected during the pop-up restaurant’s 21 day tenure. Thank you! This liquid gold will be used to fertilise 20 hectares of mustard crop, the oil of which will power the next Greenhouse restaurant.


Yep – that really is a tank of harvested urine at the entrance to
MFWF Greenhouse by Joost

The urine was harvested using Caroma waterless urinals and revolutionary Dubbletten dual bowl toilets, before being transported to Daylesford, where we will be conducting a full scale fertiliser trial starting in June.

“Urine is incredible for nitrogen, phosphorous and other trace elements. It’s so valuable – you only need the urine of 25 people to provide fertiliser for a hectare of crop.” Joost Bakker 

Whilst many people baulk at the idea of urine harvesting, throughout history people have used urine for everything from cleaning clothes to bathing, even as a medicinal cure-all. And in European countries it is a well known fertiliser of citrus. Why? Urine is rich in nitrogen (11g per standard urination), phosphorous (2.5g) and potassium (2.5g) – common components of commercial mineral fertilisers – as well as other beneficial trace elements. Additionally, the body’s urine production process creates a sterile, nutrient-dense liquid that is easily absorbed by plants when used as a fertiliser. As Håkan Jönsson of the Swedish University of Agricultural Sciences explains: “Food gives us nutrients like nitrogen as parts of complex organic molecules, but our digestive system strips them down into the basic mineral form that plants need – so we have done half the job”.

 Around the globe, researchers have successfully used urine to cultivate healthy crops including amaranth, cucumber and beetroot. A study conducted by the University of Kupio (Finland) found that urine fertiliser produced beets that were up to 27% larger than crops fertilised with industrial substances! Furthermore, results from experiments conducted by Surendra K. Pradhan comparing fertiliser types on cabbage crops showed that as well as bearing larger fruit, plants fertilised with urine grow at a quicker rate and are better resistant to pests.

 “Every day, we urinate nutrients that can fertilise plants that could be used for beautiful landscapes, food, fuel, and fibre. Instead, these nutrients are flushed away, either to be treated at high cost or discharged to waters where they over fertilise and choke off aquatic life.” Carol Steinfield, Liquid Gold

 Though it is a relatively new concept in Australia, harvesting urine for agricultural purposes is widely practised in countries such as Sweden, with the potential environmental benefits extending beyond healthy crops. Whilst Australians currently ponder how to curb our water usage, it is estimated that diverting urine could reduce a toilet’s water consumption by 80% due to the reduction of liquid used for flushing. Considering that a standard toilet can use up to 100 litres of water a day, this means significant reductions. As well as saving water, urine diversion also ensures the health of our marine life. If nitrogen isn’t properly extracted from waste water through an energy-intensive detrification process, the surplus minerals flooding into waterways cause excess algae growth which can lead to the death of plants and animals.

 “Think about Australia’s 20 million people providing fertiliser — think about the world’s 7 billion!” Joost Bakker

A loo with a view! Caroma waterless urinals and a Dubbletten dual bowl toilet

Watch this space for updates from the fertiliser trial and the development of Joost’s waterless female urinal! 

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Greenhouse by Joost Sydney - "Joost designed and made the chairs from aluminium irrigation pipes and the seats are made from leather off-cuts from a Victorian tannery. They are remarkably comfortable."

Indira Naidoo